Shaft locking device for bearing assemblies

ABSTRACT

A bearing assembly wherein the inner diameter of the slotted compressible annular locking collar is provided with a protrusion which extends radially inwardly, and finger extensions of the inner ring are provided with a recessed groove which extends at least partially along the collective outer annular surface of the finger extensions. When the locking collar is disposed about the finger extensions of the inner ring, the protrusion is disposed within the recessed groove to retain the locking collar on the inner ring. The inner ring finger extensions and the locking collar are relatively sized such that when they are in their free states, the inner diameter of the protrusion is slightly smaller than the outer diameter of the recessed groove, such that the collar may be snapped over the finger extensions and into proper position on the inner ring prior to installation on a shaft. The protrusion may be an integrally formed part of the locking collar or a separate resilient member. In one embodiment, the locking collar and finger extensions are formed with cooperating threads.

This is a divisional application of U.S. patent application Ser. No.09/235,691, filed Jan. 22, 1999, now U.S. Pat. No. 6,200,039.

FIELD OF THE INVENTION

The present invention relates to bearing assemblies, and moreparticularly, to a bearing assembly having improved means for securingthe inner bearing ring of the assembly onto a shaft.

BACKGROUND OF THE INVENTION

Various arrangements are known in the art for securing the inner bearingring of a bearing assembly onto a rotating shaft. Such arrangements haveincluded shaft engaging set screws and shaft-surrounding lockingcollars. Such locking collars include locking or tightening means,generally in the form of one or more locking screws. In the so-calledSKWEZLOC® arrangement disclosed in U.S. Pat. Nos. 4,537,519 and4,728,203, the inner ring has finger extensions which, when compressedwith a screw operated locking collar, tightly grip and hold the shaft.This finger extension/locking collar combination enhances theconcentricity of the inner ring with the shaft and facilitates rotationof the shaft at higher speeds.

Arrangements which utilize shaft-surrounding locking collars, however,have various shortcomings. Inasmuch as the locking collar is a separatecomponent from the inner bearing ring, the locking collar can becomeseparated from the bearing assembly and lost or mislaid. Moreover, ifthe locking collar is not properly disposed on the inner bearing ringduring assembly, the collar may not adequately secure the inner bearingring to the shaft. For example, if the collar is slightly cocked on theinner bearing as it is tightened, it will align itself after the shaftis rotated. This causes the collar to become loose on the inner bearing,resulting in slippage between the inner bearing ring and the shaft whensubjected to radial and/or axial loads. The problems of mounting andretaining such locking collars are compounded if the collar comprises amultiplicity of segments which must be properly positioned and tightenedduring installation.

SUMMARY OF THE INVENTION

In overcoming these problems with the prior art there is provided abearing assembly wherein the locking collar may be efficientlypre-assembled on the inner bearing ring at the factory and remainproperly positioned on the inner bearing ring during installation onto ashaft. In this way, the collar may not be readily separated from thebearing assembly and mislaid. Moreover, this preassembly ensures thatthe collar is in proper position on the inner bearing ring whichfacilitates subsequent reliable installation of the collar and innerbearing ring on the shaft.

In accomplishing these objectives, the inner diameter of thecompressible annular locking collar is provided with a protrusion whichextends radially inwardly. When the locking collar is disposed about thefinger extensions of the inner ring, the protrusion is disposed within arecessed groove which extends at least partially along the collectiveouter annular surface defined by the finger extensions for preciselylocating and orienting the collar. According to a feature of theinvention, when the inner ring finger extensions and the locking collarare in their free states, the inner diameter of the protrusion isslightly smaller than the outer diameter of the finger extension groove.In this way, the collar may be snapped over the finger extensions andinto proper position on the inner ring prior to installation on a shaft,i.e., in the factory. The locking collar then remains in proper positionon the finger extensions as the bearing assembly subsequently isinstalled onto the shaft. In one embodiment, a one-piece locking collarbody has an integrally formed protrusion adapted for snap actionengagement with a finger extension recess, in another embodiment thelocking collar has separate resilient O-ring engageable with the fingerextension recess, and in another embodiment, the locking collar andfinger extensions are formed with screws which permit threadedadvancement of the locking collar into preassembled position. In eachcase, following preassembly of the bearing assembly on a shaft, alocking screw may thereafter be tightened to deform the fingerextensions into secure engagement with the shaft.

These and other features and advantages of the invention will be morereadily apparent upon reading the following description of preferredexemplified embodiments of the invention and upon reference to theaccompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of a bearing assembly in accordance with thepresent invention;

FIG. 2 is an enlarged side elevational view of the bearing assemblyshown in FIG. 1, partially cut away;

FIG. 3 is a enlarged fragmentary section of a portion of the bearingassembly of FIGS. 1 and 2, showing the relative position of the innerring finger extensions and the locking collar as the latter is snappedover the ring extensions;

FIG. 4 is a view similar to FIG. 3 showing the relative position of thering finger extensions and locking collar upon tightening of the collar;

FIG. 5 is an enlarged cross sectional view of a portion of a bearingassembly according to a second embodiment of the invention;

FIG. 6 is an enlarged cross sectional view of a portion of a bearingassembly according to a third embodiment of the invention;

FIG. 7 is a plan view of the locking collar shown in FIG. 6.

FIG. 8 is a fragmentary section of an alternative locking collarmounting and retaining arrangement according to the present invention;

FIG. 9 is an enlarged fragmentary section of the locking collar andinner bearing ring shown in FIG. 8;

FIG. 10 is still another alternative locking collar mounting andretaining arrangement; and

FIG. 11 is an exploded view of the locking collar and inner bearing ringshown in FIG. 10.

While the invention is susceptible of various modifications andalternative constructions, certain illustrated embodiments thereof havebeen shown in the drawings and will be described below in detail. Itshould be understood, however, that there is no intention to limit theinvention to the specific forms disclosed, but on the contrary, theintention is to cover all modifications, alternative constructions andequivalents falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now more particularly to FIGS. 1 and 2 of the drawings, thereis shown an illustrative bearing assembly 10 embodying the presentinvention mounted on a shaft 12 (shown in phantom). The bearing assembly10 includes an annular inner ring 14 having a grooved raceway 16 formedin a main body portion 15 thereof. Surrounding the inner ring 14 inspaced relation thereto is an annular outer ring 18 having a groovedraceway 20 disposed in opposed relationship to the inner raceway 16, theraceways 16, 20 serving to receive in nesting relationship a pluralityof spaced balls or rolling elements 22. The rolling elements 22 in thiscase are disposed in rolling element pockets of a conventional cage 24.Preferably, the inner and outer raceways are wear hardened for extendingthe life of the bearing.

While not illustrated in the drawings, the assembly 10 includes aconvention means for lubricating movement of the rolling elements 22. Tomaintain lubrication to the rolling elements 22, the space between theinner and outer bearing rings 14, 18 is sealed by annular inner andouter flingers 26, 28 with annular seals 30 therebetween. The inner andouter flingers 26, 28 are press-fitted on the inner and outer bearingrings 14, 18, respectively, on either side of rolling element cage 22.

To facilitate mounting of the bearing assembly 10 to the shaft 12, theinner bearing ring 14 is provided with a compressible annular portion 32having a reduced diameter and which extends from the main body portion15. To maximize radial compression of the extended annular portion 32,the portion 32 is preferably provided with a plurality of axial slots 34which define a plurality of finger-like extensions 36 from a shoulder 38of the main body portion 15 of inner ring 14. The slots 34 preferablyare parallel to the axis of rotation of the shaft 12 to provide the mostdesirable attachment and performance characteristics.

The finger extensions 36 in this case are formed with an area of reducedthickness defined by a groove or recess 39 which extends annularlyaround the outer periphery of the finger extensions 36. This area ofreduced thickness or bending groove 39, which is spaced axially inwardlyfrom the distal ends of the finger extensions 36, permits a slightbending of the finger extensions 36 to facilitate securing the innerring 14 to the shaft 12, as disclosed in U.S. Pat. No. 4,537,519. Thegroove 39 in this case defines raised lip 41 having an outer cylindricalsurface 45 at the ends of the finger extensions 36.

For securing the bearing assembly 10 on the shaft 12, a one piecelocking collar 40 is concentrically disposed about the extended annularportion 32. To permit tightening of the locking collar 40 about theshaft 12, a locking screw 42 is threaded tangentially through the collar40 normal to a slot or gap 43 between the ends of the collar. The screw42 is recessed into the locking collar 40 and preferably receives anhexagonal wrench (not shown). It will be appreciated that, by tighteningthe screw 42, the ends of the locking collar 40 at the slot or gap 43(see FIG. 1) are drawn toward one another to effectively reduce theinner diameter of the collar 40 and to radially compress the fingerextensions 36 of the inner ring 14 into secure engagement with the shaft12.

To facilitate proper positioning and alignment of the collar 40 onto theinner ring 14, the breadth of collar 40 is preferably substantiallyequal or, as shown in the embodiments illustrated, slightly larger thanthe length of the finger extensions 36 to ensure that optimum lockingforce will be applied to the finger extensions 36. The breadth of thebending groove 39 in the finger extensions 36 preferably is on the orderof one half the length of the finger extensions 36 to one half thebreadth of the locking collar 40.

The collar 40 may be properly aligned or “squared” by exerting a forceon an outer side of the collar 40 to ensure that the collar 40 is fullyseated against the shoulder 38 of the inner ring 14. In this way, onecan visually determine if the collar 40 and the distal ends of thefinger extensions 36 are in the appropriate physical relationship. Itwill be appreciated by one skilled in the art that if the screw 42 istightened when the collar 40 is not yet fully or properly seated on theinner ring, the collar 40 may become loose during rotation of the shaft.As a result, when the collar 40 eventually seats itself during use, thecollar 40 will no longer provide the required locking force.

In accordance with the invention, the locking collar 40 has an inwardlydirected protrusion adapted for locating and positively retaining thelocking collar in properly oriented mounted position on the innerbearing ring for reliable long term usage. To this end, in theillustrated embodiment, as shown in FIGS. 3 and 4, the locking collarhas an inner cylindrical mounting surface 46 adapted for mounting on thecylindrical surface 45 of the finger extension lips 41 and an integrallyformed inwardly directed wedge shaped protrusion 50 which defines alocking ledge 51 and an inclined camming surface 52 which tapersradially outwardly from the ledge 51. The distance between the lockingledge 51 and the axial side of the clamping collar 40 positioned againstinner ring shoulder 38 corresponds substantially to the axial length ofthe groove 39 such that upon positioning of the protrusion into thegroove 39, the collar 40 is precisely located and retained within thegroove 39 between the shoulder 38 of the inner bearing ring and theupturned lips 41 of the finger extensions 36. Hence, the groove 39 inthis case serves a dual function as a weakening recess for the fingerextensions and a lock receiving and orienting groove for the collar 40.

In keeping with the invention, the locking collar 40 is adapted forefficient snap action preliminary factory assembly onto the inner ring14. To this end, the protrusion 50 of the clamping collar 40 has aninner diameter that is slightly less than the outer diameter of thefinger extension lips 41. In order to assemble the collar 40, it isfirst positioned into slightly surrounding relation to the fingerextension lip 41. To this end, a lead edge 58 of the camming surface 52is slightly larger than the outer diameter of the finger extension lips41. The collar 40 may then be advanced onto the finger extensions 36,with the angled or camming surface 52 of the protrusion advancing alongthe finger extensions 36 slightly flexing the fingers in an inwarddirection and the collar outwardly. As the protrusion 50 moves past thefinger extension lip 41, the finger extensions 36 and the locking collar40 return or “snap back” to their original conditions, as shown in FIG.3, automatically locating and orienting the locking collar 40 inposition on the inner ring and positively preventing its removal.

In this way, the bearing assembly 10 may be preassembled in the factoryand shipped to a customer or installation site with the collar 40properly oriented. When the bearing assembly 10 is subsequently mountedon a shaft, the locking collar screw 42 simply may be tightened tosecurely lock the assembly on the shaft, essentially eliminating thepossibility of misplacing the collar 40 during handling or incorrectlypositioning the collar onto the inner bearing ring during installation.It will be appreciated that while in the embodiment of FIGS. 1-4, theprotrusion 50 and the recess 39 extend circumferentially completelyaround the locking collar 50 and inner ring 14, alternatively, theprotrusions and recesses may be provided at circumferentially spacedlocations.

Referring now to FIG. 5, there is shown an alternative embodiment of theinvention wherein items similar to those described above having similarreference numerals with the distinguishing suffix “a” added. In thisembodiment, the outer cylindrical surface 45 a, defined the fingerextension lips 41 a, and the inner cylindrical mounting surface 46 a ofthe collar 40 a are formed with cooperating detents for releasable snapaction inter-engagement and alignment of the components during assembly.In this instance, the inner cylindrical surface 46 a of the collar 40 ais formed with an outwardly rounded or arcuate-shaped protrusion 50 aand the outer surface 45 a of the lips 41 a is formed with acomplimentary shaped recess 60 for receiving the protrusion 50 a.

The protrusion 50 a preferably is located at a distance from the side ofthe collar which seats against the inner ring shoulder 38 acorresponding substantially to the distance of the recess 60 from theshoulder 38 a. The protrusion 50 a of the collar 40 a again has an innerdiameter that is less than the diameter of the finger extension lips 41a with the curved configuration of the arcuate-shaped protrusion 50 aserving to cam and force the finger extensions 36 a and collar 40 aapart during assembly to facilitate snap action engagement therebetweenwhen the collar 40 a is properly seated on the inner ring 14 a againstthe shoulder 38 a. Again, preliminary factory assembly of the lockingcollar 40 a may be efficiently effected with the collar being properlylocated in mounted position for final tightening upon subsequentinstallation of the bearing assembly 10 a on a shaft.

Referring now to FIGS. 6 and 7, still another embodiment of theinvention is shown, wherein items similar to those described above havebeen given similar reference numerals with the distinguishing suffix “b”added. In this embodiment, the collar 40 b has a generally V-shapedprotrusion 50 b disposed at the juncture of inner cylindrical surfaces46 b, 60 of the collar 40 b. The protrusion 50 d again has a smallerinternal diameter than the lips 41 b of the finger extensions 36 b andis forced onto the finger extensions 36 b and into the groove 39 b withsnap action engagement. The inner cylindrical surfaces 46 b, 58 b of thecollar 40 b on opposite sides of the protrusion 50 b have differentdiameters so as to both be in close relationship with the cylindricalsurface 45 b of the finger extension lips 41 b and the bottom surface ofthe groove 39 b, respectively.

In contrast to the first and second embodiments of the invention, inthis embodiment the protrusion 50 b does not extend around the entireinner annular surface of the collar 40 b, but rather, only at discreetpoints, as shown in FIG. 6. It will be appreciated, however, that theinterference between the collar 40 b and the finger extensions 36 b atthese discrete points, which are preferably symmetrically disposed, issufficient to retain the components together.

Referring now to FIGS. 8-9, there is shown another embodiment of theinvention wherein items similar to those described above have been givensimilar reference numerals with the distinguishing suffix “c” added. Inthis embodiment, the protrusion of the locking collar 40 c is defined bya separate annular resilient member 55 carried within the annularopening of the locking collar 40 c. The illustrated annular resilientmember 55 is an O-ring disposed within a rectangular groove 56 formed inthe inner cylindrical surface 46 c of the locking collar and sized sothat a portion of the O-ring extends radially inwardly beyond theannular surface 46 c to form a resilient protrusion. The cylindricalinner surface 46 c of the locking collar preferably is only slightlylarger than the outer diameter of the finger extension lips 41 c suchthat upon positioning of the locking collar 40 c onto the fingerextensions 36 c the O-ring 55 is forced substantially into the groove 56and contained therein until reaching the recess or groove 39 c of thefinger extensions 36 c at which time the O-ring 55 will snap into therecess for locating and retaining the locking collar 40 c inpreassembled position adjacent the inner ring shoulder 38 c. Thedistance between side of the locking collar positionable against theinner ring shoulder 38 c and the locking collar groove 56 correspondssubstantially to the axial length of the finger extension groove 39 csuch that upon snap action engagement of the O-ring 55 into the groove39 c the locking collar 40 c is located against the shoulder 38 c.Following such preassembly of the locking collar 40 c, the locking screw42 c can be tightened to deform the finger extensions 36 c into secureengaging relationship with the shaft upon which it is mounted.

Referring now to FIGS. 10-11 still another alternative embodiment ofbearing assembly is shown wherein items similar to those described abovehave been given similar reference numerals with the distinguishingsuffix “d” added. In this embodiment, the inner cylindrical surface ofthe locking collar 40 d and the outer surface of the finger extensions36 d are formed with cooperating threads 62, 63, respectively, whichenable the locking collar 40 d to be rotatably threaded onto the fingerextensions 36 d until reaching its preassembly position in abuttingrelation with the inner ring shoulder 38 d. The threads 62, 63 in thiscase form protrusions which retain the locking collar 40 d inpreassembled position. Again, following such preassembly, tightening ofthe locking screw 42 d will deform the finger extensions into secureengagement with the shaft upon which the bearing assembly is mounted.

In summary, it will be seen from the foregoing that the inventionprovides a unique bearing assembly locking arrangement wherein thelocking collar may be preassembled onto the inner bearing ring in thefactory. The locking collar is provided with a protrusion along itsinner annular surface, and the finger extensions of the inner ring areprovided with a mating groove. Both the groove and the protrusion may beof various sizes and shapes, extending completely or partially along theannular surface, so long as the groove and protrusion are relativelysized so that there is an interference between the components when intheir free state. In this way, when the collar is preassembled onto theinner bearing ring, the collar is held in the proper position forsubsequent installation and tightening onto a shaft.

What is claimed is:
 1. A bearing assembly comprising an inner ring formounting on a shaft, an outer ring disposed concentrically about saidinner ring, a plurality of rolling elements interposed between saidinner and outer rings, said inner ring including finger extensionsextending axially from a side thereof, a collar comprising a lone pieceannular compressible member positionable circumferentially about saidfinger extensions, said finger extensions having an outer peripheryformed with threads, said one piece annular member having an innerannular mounting surface formed with threads that are engageable withsaid finger extension threads for permitting said annular member to berotatably threaded on to said finger extensions to a preassembledposition, and said annular member having a fastening screw operable forcausing said annular member to compress said finger extensions intolocking engagement with a shaft following pre-assembled positioningthereon.
 2. The bearing assembly of claim 1 in which said inner ring isformed with a locating shoulder, and said annular member is rotatablythreaded onto said finger extensions into abutting engagement with saidlocating shoulder.